The Importance of the Grape

Strangely enough, wine very rarely smells or tastes of grapes (other than Muscat). However, despite this, the grapes from which wine is made are the most important factor in taste. Wines made from the Sauvignon Blanc grape have a gooseberry and nettle tang, whereas Grenache grapes have flavours of ripe strawberries and peaches. Every variety of grape makes wine with its own hallmark flavours, and the majority of the world's wines are produced from one or more of the 15 or 20 most popular grape varieties.

To understand how wine is made, it is important to understand the different components that go to make up the grape. If you take any grape and cut it down the middle it looks much the same:

The Skin

The skin is covered in a whitish bloom which is a thin covering of wild yeasts and bacteria. The skin itself contains tannin and, in black grapes, a colouring pigment.

The Stalk

This is woody and full of tannin, which is a preservative with a bitter flavour.

The Pulp

The pulp of almost all grapes is the same colour: a pale green/yellow, and is the most interesting part of the grape in white wine making. Over 70% of the pulp is just water, but the remaining 30% contains the majority of the elements that give a wine flavour, character, and interest. These elements include fruit sugars and acids, trace minerals absorbed from the earth, and pectin, a gelling agent.

Since the juice of almost all grapes is the same pale, almost clear colour, white wines can be made from any colour of grapes. However, the winemaker must separate the juice from the skins immediately after pressing if they want to use black grapes to make a white wine. This must be done before the fermentation stage so that no colour is picked up from the skins. Champagne, Blanc de Noirs and Zinfandel are all white wines made from black grapes.

As most whites are made from green grapes, there is usually no hurry to separate the skins from the juice, since there is no danger of the juice picking up colour. However, most winemakers prefer to separate the two anyway, to prevent tannin leaching from the skins into the juice.

Almost all red wines obtain their colour from the grape skins, and so can only be made from black (or red) grapes.

The Pips

The pip contain bitter oils and are never desirable in white winemaking.

Historically, Old World producers stressed the importance of where the wine came from on the label, rather than what was in the bottle, and consumers simply didn't know what types of grapes went into the wine they were drinking.

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